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Topographic Phase Recovery from Stacked ERS Interferometry and a Low-Resolution Digital Elevation Model
- Source :
- Journal of Geophysical Research. 105(B12)
- Publication Year :
- 2000
- Publisher :
- United States: NASA Center for Aerospace Information (CASI), 2000.
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Abstract
- A hybrid approach to topographic recovery from ERS interferometry is developed and assessed. Tropospheric/ionospheric artifacts, imprecise orbital information, and layover are key issues in recovering topography and surface deformation from repeat-pass interferometry. Previously, we developed a phase gradient approach to stacking interferograms to reduce these errors and also to reduce the short-wavelength phase noise (see Sandwell arid Price [1998] and Appendix A). Here the method is extended to use a low-resolution digital elevation model to constrain long-wavelength phase errors and an iteration scheme to minimize errors in the computation of phase gradient. We demonstrate the topographic phase recovery on 16-m postings using 25 ERS synthetic aperture radar images from an area of southern California containing 2700 m of relief. On the basis of a comparison with 81 GPS monuments, the ERS derived topography has a typical absolute accuracy of better than 10 m except in areas of layover. The resulting topographic phase enables accurate two-pass, real-time interferometry even in mountainous areas where traditional phase unwrapping schemes fail. As an example, we form a topography-free (127-m perpendicular baseline) interferogram spanning 7.5 years; fringes from two major earthquakes and a seismic slip on the San Andreas Fault are clearly isolated.
- Subjects :
- Geophysics
Subjects
Details
- Language :
- English
- Volume :
- 105
- Issue :
- B12
- Database :
- NASA Technical Reports
- Journal :
- Journal of Geophysical Research
- Notes :
- NAG5-9623
- Publication Type :
- Report
- Accession number :
- edsnas.20030106430
- Document Type :
- Report
- Full Text :
- https://doi.org/10.1029/2000JB900340